As agricultural planting technologies continues to improve, high-speed precision agriculture is fast becoming the industry standard. Under these high-speed parameters, agricultural planters are required to put seeds in the ground with precise and repeatable spacing between the seeds in order to maximize crop health and yield. This seed spacing must be maintained at any ground speed. The ability to turn off seed dispensing or changing the seed dispensing rate on individual rows is also highly desirable to eliminate planting overlap and to keep seed spacing consistent across all rows on a curve.
Existing seed metering designs use mechanical meters to place the seeds at the desired spacing. Generally, seed spacing is determined in these designs by the spacing of the seed slots in the metering disc and the speed at which the meter is operated. The meter speed is typically correlated to the implement's ground speed by means of some method of mechanical transmission tied to ground engaged wheels, or, more recently, electric or hydraulic motors are utilized to decouple the meter's speed and subsequent seed spacing from the ground speed of the planter.
One disadvantage of known mechanical seed metering devices is that numerous complicated actuators, sensors, and mechanical elements are required on each row unit in order to achieve such features as row-by-row shut off, consistent seed spacing across all rows on curves, and compensation for variable ground speeds. As the number and complexity of parts in a system grows, that system inherently becomes more expensive and less reliable compared to a simpler system with fewer parts and elements.
There is a need in the art for improved systems, methods, and devices for metering seeds in high-speed planting implements.